• 한국환경보건학회지
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• 제17권2호
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• pp.1-8
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• 1991

The stochastic variance and structures of time series data on air quality were examined by employing the techniques of autocorrelation function, variance spectrum, fourier series, ARIMA model. Among the air quality properties of atmosphere, SO$_{2}$ is one of the most siginificant and widely measured parameters. In the study, the air quality data were included hourly observations on SO$_{2}$ TSP and O$_{3}$. The data were measured by automatic recording instrument installed in Kwanghwamoon during February and March in 1991. The results of study were as follows 1. Hourly air quality series varied with the domiant 24 hour periodicity and the 12 hour periodic variation was also observed. 2. The correlation coefficients between SO$_{2}$ and O$_{3}$ is -0.4735. 3. In simulating or forecasting variation in SO$_{2}$ ARIMA models are on a useful tools. The multiplicative seasonal ARIMA (1, 1, 0) (0, 2, 1)$_{24}$ model provided satisfactory results for hourly SO$_{2}$ time series.

• 한국환경보건학회지
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• 제35권2호
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• pp.116-123
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• 2009

Laboratory scale experiments were conducted to investigate the removal characteristics of nitrogen and phosphorus by the variation of aeration time in four sequencing batch reactors (SBRs). In R1 which has the shortest aeration time as 1 h, MLVSS concentration in reactor decreased by the wash-out of biomass because of the poor sedimentation. The TOC removal efficiencies were almost similar in 3 reactors except R1. At the low aeration time as 1 h, the nitrification was severely inhibited by the deficiency of oxygen. ${NH_4}^+$-N removal efficiency was decreased by the decrease of aeration time. At the aeration time over 2 h, the phosphorus removal efficiency was not affected by the variation of aeration time. The nitrification was inhibited but the phosphorus release and uptake was not inhibited by the decrease of low aeration time. Therefore, we can see that the phosphorus removal microorganisms are superior to nitrification microorganisms in oxygen utilization.

• 한국수산과학회지
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• 제36권6호
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• pp.632-640
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• 2003

Geographic variation in shell morphology of Thais clavigera $(K\"{u}ster)$ (Gastropoda: Muricidae) was investigated using samples collected from 24 sites along the Korean coast. Multivariate statistical analysis was applied to 9 morphometric and 4 categorical variables. The shells of T. clavigera were classified into two distinct morph types (Type-W and -E). Temperature and salinity of the sampling sites were significantly correlated with the incidence of morph types. Relative abundance of Type-W (thin, yellowish brown shell with triangular nodules) was positively correlated with temperature and negatively correlated with salinity. In contrast, relative abundance of Type-E (thick, dark purple shell with round nodules) was negatively correlated with temperature and positively correlated with salinity. Possible correlation between environmental factors (temperature and salinity) and morphological variations in the shells were discussed.

• 한국지구과학회지
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• 제28권5호
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• pp.556-562
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• 2007

The interdecadal variation of wintertime blocking frequency over the Siberia ($60^{\circ}E-140^{\circ}E$) is examined using the ECMWF/NCEP-NCAR re-analysis data for the period 1958-2006. The wintertime blocking frequency over the Siberia significantly decreased for the period 1986-2006, compared to the period 1958-1985, which is mainly due to the anomalous circulation of 500-hPa geopotential height field. During the period 1986-2006, there was enhancement in both the anomalous cyclonic flow over the western Siberia and the anomalous anticyclonic flow over the east Asia. These anomalous circulation patterns, which might be associated with changes in surface temperatures over the Asian continent, are suspected to playa possibly important role as an obstacle to the formation of blocking flow over the Siberia.

• 한국물환경학회지
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• 제27권1호
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• pp.9-18
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• 2011

In this study the optimal volume for non-point source control retention is estimated considering spatio-temporal variation of land surface. The 3-parameter mixed exponential probability density function is used to represent the statistical properties of rainfall events, and NRCS-CN method is applied as rainfall-runoff transformation. The catchment drainage area is divided into individual $30m{\times}30m$ cells, and runoff curve number is estimated at each cell. Using the derived probability density function theory, the stormwater probability density function at each cell is derived from the rainfall probability density function and NRCS-CN rainfall-runoff transformation. Considering the antecedent soil moisture condition at each cell and the spatial variation of CN value at the whole catchment drainage area, the ensemble stormwater capture curve is established to estimate the optimal volume for an non-point source control retention. The comparison between spatio-temporally varied land surface and constant land surface is presented as a case study for a urban drainage area.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
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• pp.192-195
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• 2003

To identify the difference between Korean-Chinese and Korean children's variation of pulmonary function with personal factors (suck as age, height, and weight), we performed pulmonary function test (PFT) and measured personal factors of 200 Korean-Chinese children participants from two elementary schools of Beijing and Melons city in China. Regression analysis was utilized to determine which personal factors were significantly correlated with PFT measure (FVC and FEV$_1$). We compared the regression model from this study with those of other studies of Korean children. Similar to other studies, we found that the most important variable, influencing PFT measure, was height, whereas addition of either age or weight in the regression virtually did not increase the accuracy. As the result of comparison of the regression model from this study with those of other studies of Korean children, variation in FVC or FEV$_1$ with height were similar.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 1998년도 봄 학술발표회 프로그램
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• pp.122-124
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• 1998

• 한국환경과학회지
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• 제17권10호
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• pp.1075-1080
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• 2008

The influence of the point source inflow on the water quality variation in the downstream of Hyeongsan River was investigated. As the results of seasonal variation, the pollutant concentrations of dry season were 1.5-4 times higher than those of wet season. The increase rate of $BOD_5$, $COD_{Mn}$, T-N, T-P due to point source were ranged to $8.1\sim42.6%$, $7.3\sim41.9%$ and $17.1\sim207%$ as the inflow of P1, P2 and P3, respectively. After P1, P2 and P3 inflow, the accumulated increase rate were 64.3%, 32.6%, 93.1% and 258.9% in $BOD_5$, $COD_{Mn}$, T-N, T-P, respectively. It was found that the influence of point source inflow on the water quality in the downstream of Hyeongsan River is severe.

• 한국환경과학회지
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• 제11권6호
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• pp.583-588
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• 2002

Heavy metals like Mercury and Cadmium cause various kinds of toxicities in the organs of Liver and Kidney. To observe the results of toxicity in the liver, kidney, and serum when the rats were injected subcutaneously with HgCl$_2$ and CdC1$_2$ and sacrificed after 24 hours and 72 hours from the last injection, we measured variation of lipidperoxide values in rat liver homogenate, variation of aspartate aminotransferase and alanine aminotransferase in rat serum. Variation of lipidperoxide values in rat kidney homogenate and variation of BUN in rat serum. It was found that Mercury and Cadmium administered subcutaneously to the skin in the air could cause the damages of liver and kidney.

• 한국환경과학회지
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• 제7권5호
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• pp.725-733
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• 1998

Three numerical experiments are done using IAP(Institute of Atmospheric Physics) global spectral model(T42L9) to investigate the influence of the surface temperatures on the 7-day simulation. Particularly, the response of the subtropical High in summer to the variation of soil temperature and sea surface temperature(SST) was emphasized through a series of experiments. Experiment 1 uses the June climate data as the earth surface conditions. Experiment 2 is similar to Experiment 1 except for the soil surface temperature. Experiment 3 is the same as Experiment 1 except for the modified SST, which is much warmer than the June climate SST on the sea around the Korean peninsula. The main finding in 7-day simulation is that the response of the subtropical high in summer to the variation of the sell surface temperature was much more than that to the variation of the SST. It is implied that the proper treatment of sell surface temperature is more important than that of the SST for the better 7-day simulation of the subtropical high in summer.